In order to meet increasing demands for wireless data traffic after the commercialization of fourth-generation (4G) communication systems, efforts have been made to develop advanced fifth-generation (5G) communication systems or pre-5G communication systems. This is one reason why 5G communication systems or pre-5G communication systems are called beyond 4G network communication systems or post long term evolution (LTE) systems.
To achieve a high data transmission rate, 5G communication systems are being developed to be implemented in an ultrahigh frequency band (mmWave, for example, a 60-GHz band). In order to reduce the occurrence of stray radio waves in an ultrahigh frequency band and to increase the transmission distance of radio waves in 5G communication systems, technologies are under discussion, for example, beam-forming, massive multiple-input and multiple-output (massive MIMO), full dimension MIMO (FD-MIMO), array antennas, and analog beam-forming, large-scale antennas.
Further, in order to improve a system network, for 5G communication systems, technologies have been developed, for example, evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device-to-device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), interference cancellation, etc.
In addition, for 5G communication systems, other technologies have been developed, for example, advanced coding modulation (ACM), such as hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC), and advanced access schemes, such as filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).
Terminals for communication systems include electronic terminals in a wearable form. Such electronic terminals are generally called wearable devices, and various forms of wearable devices are being developed. For example, the wearable devices may be provided in various forms that are attachable to the human body or clothes, such as head-mounted (glasses) type, wrist-wearable (watch or wristband) type, contact lens type, ring type, shoes type, clothes type, and the like. The wearable devices enable an electronic terminal to be worn on the body, like clothes or glasses, thereby increasing portability and accessibility.
Among various forms of wearable electronic terminals, for example, head-mounted wearable devices, such as a head-mounted display (HMD), are largely being developed. An HMD may provide a video service in a see-through form that provides augmented reality (AR) and in a see-closed form that provides virtual reality (VR).
The see-through form composes or combines a virtual subject or object with the real world using characteristics of a transflective lens to provide reinforced additional pieces of information that are difficult to obtain only with the real world. The see-closed form is a form of two displays placed before the user's eyes, which allows the user to enjoy content (game, movie, streaming, broadcast, and the like), provided via an external input, on a separate screen alone, thereby providing an excellent sense of immersion.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.